Pre-Implantation
Fertilization...
Spem fertalizing the Egg
Spem fertalizing the Egg

--Begins with the union of sperm and egg
--Only one sperm can fertilize an egg


During Fertilization...
--Sperm releases enzymes that pierce through the egg's coating
--Sperm’s surface proteins bind to the egg's receptor protein
--Sperm and egg plasma membranes fuse and nuclei unite
--Changes in the egg membrane prevents entry of additional sperm
--Fertilization egg called (zygote)
--Develops into embryo


Zygote to Blastula through cleavage
Zygote to Blastula through cleavage


Embryonic Development

1)
Zygote
Sperm fertilizes eggs
Cleavage-rapid series of cell division- first few mitotic cell division
2) Morula
Consists of a solid ball of cells
Embryonic stem cells phase
3) Blastula
During each mitotic division the embryo does not increase is size the existing cytoplasm divides
Implantation--When blastocyst attaches to the uterine wall
4) Gastrula
Formation of the 3 germ layers
-Endoderm-inner most layer-becomes organs
-Mesoderm-middle layer-becomes muscles
-Ectoderm-outer most layer-becomes skin